Univention Corporate Server 4.1 erratum 86 (bugfix)

This update addresses the following issues:
* A problem regarding IMAP ACLs at shared folders with primary mail address
has been fixed. ACLs that have been removed via Univention Management
Console or CLI have not been removed on the IMAP server (Bug 40194).
* A file for the process of handling user renames has been moved to a
secure location (Bug 40246).